System of generating power and control therefor



Jan. 23,1934. w. M. c oss 1, 2

SYSTEM OF GENERATING POWER AND CONTROL THEREFOR Original Filed March 12, 1925' 3 Sheets-Sheet 1 W'HWHTHWHWHW IN V EN TOR.

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Jan. 23, 19340 w. M. CROSS I 1,944,222

SYSTEM OF GENERATING POWER AND CONTROL THEREFOR Original Fil'ed March 12. 1925 3 Sheets-Sheet 2 I N VEN TOR.

Jan. 23, 1934. w. M. 020% 1,944,222

SYSTEM OF GENERATING POWER AND CONTROL THEREFOR Original Filed March 12. 1925 3 Sheets-Sheet 3 I N VEN TOR.

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Patented Jan. 23, 1934 UNITED STATES PATENT OFFICE SYSTEM OF GENERATING POWER AND CONTRGL THEREFOR Application March 12,

1925, Serial No. 14,953

Renewed September 9, 1932 2 Claims.

This invention relates to improvements in a system of generating power and a method of control therefor, and refers more particularly to a process in which work is extracted from a fluid medium such as steam at high temperatures and pressures.

Among the objects of the invention are, to provide a system comprising a particular type of heater construction for raising the temperature 10, of the work transmitting medium to a superheated condition under high pressure and passing it through successive stages of expansion and reheating, the expansion stages being designated as the power stages; to provide a system which consists of a primary heating stage comprising preheating and vaporizing zones followed by a primary expansion stage, and a plurality of successive reheating and expansion stages alternately arranged in order that the steam or medium utilized for transmitting the power is permitted to expand to a temperature where there is no appreciable condensation or substantially to a temperature above its wet point; to provide a system in which the amount of reheating is automatically and definitely controlled by an automatic thermostatic mechanism which injects a cooling medium into the system with the formation or existence of excessive temperatures, particularly in the reheating stages; to provide a system in which there is further regulation in that the temperature in the primary heating stage is controlled by the discharge temperature and pressure automatically regulating the firing of the heater'and the inflow of charging liquid respectively, and further, to provide a system hereinafter explained in more detail.

Fig. 1 is a plan view of the heater construction with the top baffle removed; showing the arrangement of the heating tubes.

40 s Fig. 2 is a view taken along the line 27-2 in Fig- 1.

Fig. 3 is a diagrammatic arrangement of the tube ends at one side of the horseshoe construction, with the headers removed and the tube ends connected up in series to disclose more clearly the travel of the medium from its introduction to discharge. The automatic arrangement is also diagrammatically shown in this figure.

Fig. 4 is a detail of the automtaic temperature control shown in Fig. 3.

Fig. 5 isa cross sectional view of the pressure regulating valve used in the fuel line to the burners in Fig. 3 to regulate the fuel supply to the burners.

Referring to the drawings, at 1 is shown a heavily insulated furnace enclosure built in a horseshoe shape and supported by I beams shown at 2. Upon the bed of the furnace designated as 3 in Fig. 2 are supported two tunnel furnaces 4 which are fired by burners not shown, 60 supplied by the fuel lines 5 controlled by valves 6. These separate fuel pipes are fed by a main fuel line '7 and a preheated air line 8 connected into the fuel pipe by a T connection 9. The roof of the furnace is supported or hung, by suspension brackets not shown. Below the roof is a heavily insulated baffle or combustion gas diverting ceiling structure 10. Supported on the base, and between the base and top baffle, are three vertical banks of tubes bent in a horseshoe shape and designated as preheating tubes 11, vaporizing tubes 12 and superheating and reheating tubes 13. As described, the tubes are bent into a horseshoe shape back upon themselves so that both of the ends of each tube terminate in the front of the furnace and are rolled into headers designated as 11 12 and 13 11 12 and 13, respectively. There are also a bank or overhead set of vaporizing tubes designated in the drawings as 14 and connected to front and rear headers 14 so, and 14, respectively. These overhead vaporizing tubes are connected to'the vaporizing tubes arranged in the vertical bank designated as 12 in a manner shown in Fig. 3 hereinafter explained.

Referring now to the manner in which the fluid medium, which is supplied to the tubes, is heated, fuel drawn from any convenient source is forced through the line '7 into the separate burners which are positioned in the tunnel furnaces 4. These furnaces. are preferably formed of carborundumbrick in order to withstand very high temperatures; in fact, the heat from these furnaces is primarily radiant heat given off from their walls. The combustion gases which are discharged from small ports in the sides of the tunnels pass laterally through the spaces between tubes in directions shown by the arrows, the heat radiating from the tunnels in all directions heating the tubes on all sides and at the top of the furnace. Combustion gases pass upwardly from the sides of the baiile through the vertical lines '15 and top horizontal fines 16 into a common flue 1'7 at the top. In this flue 17 is positioned a preheater' 18 which serves to raise the temperature of the incoming air supplied through the line 19. After being heated in the preheater' 18, the air is directed through the insulated line 8 and is introduced with the fuel in controlled quantities to the burners. This preheating of the air not only reduces the temperature of the flue gases, but

materially increases the efficiency of the fuel combustion.

Passing now to the travel of the fluid medium which is usedfor transmitting the heat from the furnace to' the separate stages of expansion or power stages, water or other suitable transmitting medium is introduced through the line 20. It is charged by means of a pump 21 through the line 22 which is connected to the inlet end of the preheating tubes 11. In order to more clearly designate the travel of the heat through the tubes, in Fig. 3 the tube ends of the three separate stages-namely, the preheating, vaporizing and superheating stages,-'-have been connected up as though the tube ends were joined by means of return bends. To follow the travel of the medium, it must be kept in mind that on introduction to the initial preheating tube the water will be directed around the curved or horseshoe shaped tube to its other extremity, terminating in the header at the opp'osite side of the furnace designated at 11'. By partitions in the headers 11*, the water or fluid is then directed into the next succeeding tube and returned to the header 11" from which it isagain shuttled backward and forwardthrough the entire bank of preheating tubes. Ondischarge from the final preheating tube through the line 23, the preheated fluid is circulated through the vaporizing tubes 12 in a likemanner to its circulation through the preheating tubes. From the vaporizing tubes it is passed thrcugh the line 24 shown in Fig. 3 to the bank of vaporizing tubes positioned above the fire zone. In this set of tubes the circulation is inerelyzigz'ag, the flow being reversed in each successive tube from the inlet to the outlet by means of partitions in the headers which have theeffect of return bends. From the final compartment in the header connected to the outlet end of the last tube, the vaporized medium passes through the line 25 into the superheater tubes which are divided vertically into three sections designated as the superheater 13, the first reheater 13 and the second reheater 13. The vapcrizedmaterialpassing into the tubes 13 is given a superheatand is discharged in this superheated condition through the line 26 to the initial expansion stage or what, in the drawings, is des ignated as No, 1 engine and numeral 2'7. While being designated as an engine, it may take the form of any suitable power source, such as a turbin, reciprocating or rotary mechanism. In a like manner, No. 2 and No. 3 engines, while designated as such, may be any suitable type of mechanism from which power may be delivered. w Subsequent to expansion, the medium, which has been expanded to a point where there is no appreciable condensation or not below its wet paint, is discharged through the line 28 back into the first reheater 13 In this stage it is raised ihtemperature and directed through the line 29 to the second expansion stage 30 which, as stated, may be any suitable power mechanism. From the second expansion stage 30, the discharge travels back through the line 31 to the second heater 13 and after reheat, passes through the line 32 to the third expansion stage 33, the exhaust from which passes out'through the line 34 to a condenser 35 from which the condensed medium Inlay be passed to a surge tank and returned to the initial inlet line 20 or be discharged asv'vaste.

Referring now to the method of automatically ccntrollin'g the temperature given to the fluid medium in the initial stages, including the preheating and vaporizing stages. In the discharge line 25 from the vaporizing tubes is interposed an automatic temperature control which regulates the feed by means of a mechanism shown diagrammatically in Fig. 4. It is understood that the mechanism shown is rather crude in construction and utilized solely for the purpose of disclosing, in a simple manner. an invention which it is desired to cover broadly.

Briefly, the heated fluid coming in contact with the closed end of the thermostat or pipe 36 enclosed in a casing 37 causes the expansion and contraction of an expansive medium with which the pipe 36 is filled; -This medium, acting upon the diaphragm 38 either opens or closes the valve 39 acting against the compression spring 40 permitting a greater or less flow of charging fluid to pass into the preheating tubes. The casing enclosing the thermostat is designated as 37 in Figs. 3 and 4, while the bonnet diaphragm valve controlling the inflow is designated as a whole in Fig. 3 as 41. A further control of the heat of the combustion gases is an automatic pressure control of the firing or the amount of fuel which is supplied to the burners. For this purpose, a pressure line 42 is tapped into the line 25 and is connected to a bonnet diaphragmvalve 43, a section of which is shown in Fig. 5. The pressure acting upon the diaphragm designated as 44 closes 61' opens a valve 45 acting against a compression spring 46 which regulates the amount of fuel per: mitted to flow through the line 7 into the burners. By means of this automatic temperature contrdl of the feed and the automatic pressure control of the firing, a constant and uniform tempera: ture may be maintained in the furnaceand a better control and efficiency of the general oper ating conditions.

Passing now to the regulating of the temper= ature of the fluid supplied to the separate stages of expansion, the system and controls of the initial stages are so arranged that the temperature of discharge from the superheater is proper for the first expansion stage 27. After reheat, how= ever, in the second stage, the temperature of the fluid may be somewhat excessive. In this event, the fluid passing through the casing of the ther mostat 47 will heat the expansive liquid contained in the pipe 48 manipulating a bonnet diaphragm valve 49 similar in construction to that shown in Fig. 4, permitting the injection of a cooling rhe'dium, such as water, through the line 50 nterns exhaust line 28 from expansion stage 27. This injection of a cooling medium into the exhaust line 28 or into the inlet line of the first preheatei", will temper the heating effect in this stage and will reduce the temperature of the medium fidwing to the second expansion stage 30 to the dc sired extent. When this temperature has been reduced to proper operating conditions for the second expansion stage, the thermostat will 'autb matically reduce the amount of coolingmedium injected by manipulation of the valve 49. 'In a like manner, should the discharge from the secits 0nd reheater or the temperature of the inflow of the thermostat 51 will shut off the amount of Water injected as a tempering medium.

By this automatic control, both in the primary stages and the separate reheating stages, a separate control of the stages is accomplished, producing a uniform system wherein there are not permitted for any appreciable period of time any excessive conditions of temperature or pressure which rapidly tend to deteriorate the apparatus.

As stated, the system is operated under high pressures ranging from 1,000 to 2,000 pounds per square inch more or less in the initial stage of expansion, reducing as much as 500 pounds in each reduction or expansion stage. The fluid medium, which may be water, mercury, sulphur dioxide or other materials adopted for the particular type of work, is circulated at high velocity in order to rapidly carry off the heat, for by rapid elimination of heat it is impossible to fire the furnace at much higher temperature.

It will be further understood that, although but three stages of expansion and reheat are shown, a plurality or any number of stages may be used according to the range of temperatures and pressures available,--the principle involved being that the medium or discharge from the initial stage of superheat is at a high temperature and pressure, and in each successive expansion stage there is extracted from the medium, with the reduction in pressure, Work contained therein Without reducing the medium to a condition where any appreciable amount of condensation takes place. The reheating stages carry up this temperature in order to ofiset the condensing effect of the next pressure reduction.

While the travel of the medium has been disclosed as passed through a single tube in a continuous passage, the invention must not be interpreted as being limited to this mode of operation, as two or more tubes may be manifolded together, forming a continuous passage for medium through the system.

Where the invention is adapted to use as a land boiler, using water contaminated with minerals as distinguished from distilled water used at sea, a header type of construction may be substituted for the curved tubes in order to facilitate cleaning. The boiler constructions shown in the drawings is particularly adapted for marine purposes where distilled feed water is used.

I claim as my invention:

1. The combination with a high pressure vapor pressure generator and furnace, of a liquid supply for the generator and means supplying elements of combustion to the furnace, a vapor superheater, successive stages of vapor pressure expansion, a vapor reheater between each stage, means controlled by the temperature of the vapor entering the superheater for regulating the amount of liquid delivered to the generator, pressure operated means controlling the elements of combustion, and vapor cooling means associated with the entrance to each reheater and including a temperature responsive device associated with the entrance to the expansion stage served thereby to deliver vapor of predetermined heat value to each expansion stage.

2. In combination, a high pressure vapor generator including a multiplicity of long small bore fluid conduits in parallel'and a vapor consuming system in several stages, means maintaining liquid throughout a preponderance of the length of each conduit, means regulated by a physical characteristic of the fluid in the generator for supplying heat to the generator, a superheater receiving the fluid from the conduits, means regulating the amount of liquid in the conduits to deliver saturated steam only to the superheater, a reheater between some of the stages of the vapor consuming system, and means admitting fluid to the entrance of the reheater in accordance with a predetermined temperature of the fluid beyond the outlet of said reheater.

WALTER M. CROSS.

CERTIi ICATE 0F CORRECTION.

Patent No. 1,944, 222. January 23, 1934.

WALTER M. (moss.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correetion as follows: Page 3, line 19, for "impossible" read possible; and that the said Letters Patent shouid be read with this correetioe therein ihat the same may conform to the record of the case in the Patent Office.

Signed and seaied this ilth day of September, A. D. 1934.

Leslie Frazer (Sea!) Acting Commissioner of Patents. 

